The health body described the consequences of a further international spread of the virus as“particularly serious” due to its virulence.
“A coordinated international response is deemed essential to stop and reverse the international spread of Ebola,” the WHO said in a statement after a two-day meeting of its emergency committee on Ebola.
WHO announced an international health emergency over Ebola, calling the current outbreak the most severe since 1976, when the virus was first identified in humans.
The organization previously declared similar emergencies for the swine flu pandemic in 2009 and for polio this May.
The declaration of an international emergency is aimed at increasing the level of vigilance for transmission of the virus.
All states with Ebola transmission – Guinea, Liberia, Nigeria and Sierra Leone – should declare a national emergency, WHO said, adding that the outbreak shouldn’t prevent international trade and travel.
“Countries affected to date simply do not have the capacity to manage an outbreak of this size and complexity on their own,” Dr. Margaret Chan, WHO chief, said at a news conference in Geneva. “I urge the international community to provide this support on the most urgent basis possible.”
The spread of Ebola could be stopped if infected people are dealt with properly, Keiji Fukuda, WHO’s head of health security, said.
“This is not a mysterious disease. This is an infectious disease that can be contained,” he stressed. “It is not a virus that is spread through the air.”
The organization explained the rapid spreading of the virus by the weaknesses of the health systems of the affected states in West Africa.
The inexperience of local medics and misperception of the Ebola virus “continue to be a major challenge in some communities,” the health body added.
Global alarm over the spread of the disease increased in July when an American citizen died in Nigeria after traveling there by plane from Liberia.
The current outbreak of Ebola, which began in Guinea in March and spread to Sierra Leone and Liberia, has already claimed nearly 1,000 lives.